Over the past fifteen years, continual advances in microprocessor technology have pushed the performance of personal computers to increasingly higher levels. New applications for personal computers have required significant processing power, and also have required significant amounts of data to be transferred between the computer's central processing unit and peripheral devices. This has prompted attempts to improve the manner in which peripheral devices communicate with the processor. And as a result, many changes have been made to the manner in which peripheral devices and the like are attached to the processor.
Normally, peripheral devices communicate with the processor through some form of an expansion bus. One of the earliest bus architectures used for personal computers is what has become known as the AT Attachment or the Industry Standard Architecture (ISA) bus. Over the years, however, additional expansion bus architectures have been developed, some of which have become part of mainstream personal computing. These additional architectures include IBM's Micro Channel Architecture (MCA) bus, and the Extended ISA bus (EISA) bus. More recently, local bus or mezzanine bus architectures, such as the VL bus architecture and the Peripheral Component Interconnect (PCI) bus architecture, have become a standard feature in modern personal computers.
As the evolution of expansion busses has progressed, peripheral devices once attached to the ISA bus (or some other legacy bus) have been moved to more modern and higher performance buses, such as the PCI bus. For example, it is now common for the video controller and the hard drive controller, once found on the ISA bus, to be attached to the higher-performance PCI bus.
Nevertheless, most modern computers still typically include the legacy ISA bus for accommodating other older, legacy devices. Although many peripherals are no longer attached to the ISA bus, one common device that does remain on the ISA bus is the ROM BIOS. This device has remained on the ISA bus for a number of reasons, including the fact that moving it to another bus is not easily accomplished. Thus, a need exists for moving the ROM BIOS to a different bus.